Encounters with ladybugs, those small, often brightly colored insects, are common and frequently spark curiosity. People often wonder why these insects land on them. Understanding their behaviors and biology can shed light on this phenomenon, offering practical insights.
Why Ladybugs Land on People
Ladybugs are drawn to warmth, which explains why they might land on a person. As ectothermic creatures, they rely on external heat sources to regulate their body temperature, especially as cooler weather approaches. During late summer and autumn, ladybugs actively seek sheltered, warm spots to prepare for overwintering.
Their attraction to light, particularly natural sunlight, also plays a role. Ladybugs congregate on sun-warmed surfaces, and a person standing in direct sunlight can inadvertently become an appealing landing spot. This behavior is linked to their need for thermoregulation. Additionally, the bright colors of clothing can sometimes mimic flowers or favorable habitats, subtly attracting these insects.
Distinguishing Ladybug Species
The term “ladybug” refers to various species within the Coccinellidae family, and not all behave identically. A common species often encountered, especially indoors, is the Multicolored Asian Lady Beetle (Harmonia axyridis), an introduced species brought to control agricultural pests. Native ladybugs typically remain outdoors, preferring natural shelters for overwintering.
Visually, the Multicolored Asian Lady Beetle can be identified by an “M” or “W” shaped marking behind its head, a feature generally absent in native ladybugs. These beetles also exhibit a wider range of colors, including orange, yellow, and black, compared to the true red of many native species. Asian Lady Beetles tend to be slightly larger and more oval-shaped than the rounder native ladybugs. Their propensity to aggregate in large numbers and seek indoor shelter during cooler months often increases human encounters.
Are Ladybugs Harmful?
Ladybugs are generally considered harmless insects, posing no significant threat to humans. They are beneficial in gardens due to their appetite for pests like aphids. While some species, particularly the Multicolored Asian Lady Beetle, may “bite” or pinch, it is typically a minor sensation, and does not cause serious injury or transmit diseases.
When disturbed, ladybugs release a yellowish, foul-smelling fluid called hemolymph from their leg joints. This fluid can stain surfaces and may cause mild allergic reactions such as skin irritation, itching, or swelling upon contact. Respiratory symptoms like sneezing, runny nose, or asthma-like reactions can occur if ladybug allergens are inhaled, especially during large indoor infestations. Despite these possible reactions, ladybugs are not known to carry human diseases.
Managing Ladybug Encounters
When ladybugs enter homes, gentle methods can be employed for their removal. Sweeping them into a dustpan or using a vacuum cleaner with a stocking placed over the nozzle allows for easy collection without harming the insects. After collection, they can be released outdoors. This approach avoids crushing them, which can trigger the release of their staining hemolymph.
Preventative measures are effective for keeping ladybugs out of indoor spaces. Sealing cracks and gaps around windows, doors, and utility lines before autumn can block their entry points. Repairing damaged window screens and ensuring proper door seals also helps deter them. Natural deterrents like planting chrysanthemums, which ladybugs dislike, or using essential oils such as mint, citronella, or lavender around entryways can discourage their presence. Since ladybugs are beneficial insects in outdoor ecosystems, it is best to avoid using harsh chemical pesticides. Outdoor encounters are usually temporary, reflecting their natural behaviors, and often require no intervention.